Separation of formic acid from other fatty acids



Patented Mar. 5, 1935 SEPARATION or FoaMIoAom FROM OTHER FATTY ACIDS Hyym E. Buc, Roselle, N. J., assignor to Standard 7 Oil Development Company No Drawing. Application November 2, 1929, Serial No. 404,512

13 Claims. (Cl. 260122) This invention relates to a process of separating air. A determination of formic acid on the solid formic acid from its mixture with other fatty residue showed that 90.3 per cent. of the formic acids such as acetic acid, propionic acid, etc, acid had been removed, whereas only about 13% whereby more valuable products are obtained for of the acetic acid had been neutralized. various purposes such as esterification of alcohols, Example 3.-Experiment (2) was repeated using 5 etc. 1.9 kilograms of anhydrous sodium carbonate in- The invention will be fully understood from the stead of calcium oxide. 91.4% of the formic acid following description and the examples given by was removed and only 13% of the acetic acid. way of illustration. These examples indicate that it is possible to It is known to those skilled in the art that fatty remove most of the formic acid by onev treatment acids may be prepared by the oxidation of satwith a suitable alkaline material, preferably an urated hydrocarbons. There are such oxidation alkali metal or alkaline earth metal base. I may processes known which give a mixture of fatty however, use with less advantage aluminum hyacids in which formic acid forms a substantial drates, zinc oxide or in general any basic material part of the mixture. Such an acid mixture would which will react preferentially with formic acid to 5 be unsuitable for purposes of esterification of alform a precipitable salt. The treating may be cohols such as ethyl, isopropyl, etc., the esters of carried out at atmospheric temperature or below which are used as solvents for cellulose nitrates that, but considerably higher temperatures may and other organic compounds. The presence of also be employed. substantial amounts of formic acid is undesirable Having thus described my invention and illus- 20 in the acid used for esterification because it trated with examples,

hydrolyzes readily and gives an acidity which is I claim: known to be undesirable in those solvents. Small 1. The method of removing formic acid from amounts of formic acid may be present in the acid its mixture with other fatty acids which commixture without considerable disadvantage since prises, partially neutralizing the acid mixture 25 formic esters are removed during the purification with a base, and separating the neutralized prodof the ester mixture. ucts from said mixture, whereby the proportion I have discovered that formic acid may be of formic acid in the mixture is decreased. substantially completely separated from its mix-. 2. The method according to claim 1, in which 61118 t Qther fatty acids y P selective the partial neutralization is effected by addition 30 neutralization as shown by the following exof an alkaline earth metal ham amples: 3. The method according to claim 1, in which Emmple was Prepared the partial neutralization is eireoted by addition mg 41 parts by welght of an 85% solution of forrmc of an anhydrous alkaline earth base acid and 227 parts of glacial acetic acid An 4'. The method according to claim 1, in which 35 analysis for formic acid showed this mixture to the amount of base added to the acid mixture contain 13% of formic acid. To 50 parts of this is at least equivalent to the amount of formic solution, there was slowly added, without heating acid present 5.8 parts of calcium oxide. This was an amount The method of removing formic acid from 4 of alkali more than suflicient to neutralize the its mixture with other fatty acids which formic acid, but less than sufiicient to neutralize both the formic and acetic acids. The mixture pnses Partmuy neutrahzm? the fixture was centrifuged and the liquid separated from with a to i Salts m gi i the precipitated salt. A determination of formic Solvent Winch leave zf i 9 acid in the liquid showed that about 91.5% of it Salts uI 1d1SS1V an mg 8 5a S had been removed, whereas only about 9% of said mixture, whereby the proportion of formic acid in that mixture is decreased due to the prefacetic acid had been neutralized.

Example 2.-8 kilograms of the untreated acetic erentlal neutrahzatlon of formlc mildacid in formic acid solution described in Example The method according to claim in w ch 1 were dis l d i 400 m of petroleum naph the partial neutralization is effected by addition tha that boils at 100 to 275 known as normal of a alkali metal base.

benzine. One kilogram of calcium oxide was 7. The method accordin to claim 5 in which added without heating and after a period of shakthe partial neutralization is effected by addition ing, the benzine was poured off, the solid washed of an anhydrous alkali-metal base.

twice with benzine and then dried with a blast of 8. The method according to claim 1, in which 55 the partial neutralization is effected by addition of an anhydrous base.

9. The method according to claim 1, in which the base used is a base of a metal of the group consisting of the alkali and alkaline earth metals.

10. The method of removing formic acid from its mixture. with other fatty acids, which comprises partially neutralizing the acid mixture with a base in thepres'ence'of a hydrocarbon solvent for the acids to form insoluble formates, and

separating the resulting salts from said mixture, thereby decreasing the proportion. of formic acid in the mixture.

11. The method according toclaim 10. carried out in the presence of only a small amount of water.

12. In the manufacture of fatty acids by oxiits mixture with acetic acid and other fatty acids 10 produced by the oxidation of hydrocarbons, which comprises partially neutralizing the acid mixture with calcium oxide, and separating the precipitated products from said mixture, whereby the proportion of formic acid in that mixture 15 is decreased.

' HYYM E. BUC. 

